People infected with Omicron do NOT stop being infectious sooner than they did with past variants, scientist claims
- Dutch virologist says she is ‘not convinced’ Omicron infectious period is shorter
- Countries shortening isolation period are doing so because variant is less severe
- Studies suggest Omicron is shed from 2 days before to 7 days after symptoms
People infected with Omicron do not clear the virus quicker than those who had earlier strains, a scientist has claimed.
Many scientists believe that part of what makes the variant so transmissible is how quickly someone becomes infectious after catching it.
That theory, which also assumes people shake Omicron off quicker, has seen most countries reduce or even entirely scrap the seven-day isolation period for positive cases.
But Dr Marjolein Irwin-Knoester, a virologist from the University of Groningen in the Netherlands, said she is ‘not convinced’ by the data to support the assumption.
She pointed to a number of laboratory studies which still suggest Omicron carriers are infectious two days before symptoms start to seven days after onset – in line with other strains.
Dr Irwin-Knoester will tell a medical conference in Lisbon that a new variant could throw everything ‘up in the air’ again, if nations stick to their reduced quarantine times.
She did, however, admit that Omicron’s reduced severity made it ‘acceptable’ at the moment.
Studies have so far suggested a person who catches Omicron can pass the virus on to others from around two days before symptoms start to seven days after onset – in line with other strains. Data from Oxford University researchers (shown in graph) suggests almost all transmission occurs shortly before and after symptom onset
Organ donation from people who died with Covid is ‘safe’, scientists say
Organs of people who died with Covid are safe to give to transplant patients who have been vaccinated or previously infected, scientists say.
Organ replacement surgery ‘fell significantly’ worldwide when the pandemic hit, with kidney, lung and liver transplants the worst affected.
In England, transplant operations fell by 20 per cent in the first year of the pandemic.
But Professor Paolo Grossi, an infectious disease expert from the University of Insubria in Varese, Italy, said ‘evidence is continuing to build’ that organ donation from people who have previously been infected is ‘safe’.
And even organs from donors with an ‘active Covid infection can be considered’ if their infection was asymptomatic and the virus was not the cause of their death.
Professor Grossi is tomorrow set to tell the European Congress of Clinical Microbiology and Infectious Diseases, said: ‘Based on growing worldwide experience, we believe that organs from donors with past or active SARS-CoV-2 infection may be safely offered to candidates with immunity against SARS-CoV-2 because of previous infection or vaccination.
‘This might contribute to increase the donor pool.’
He also pointed to 10 liver transplant recipients in Italy, two of whom had Covid infections, while eight previously had the virus.
One of those infected subsequently died from a bacterial infection following the transplant, but the other nine patients survived.
Her comments come a month after the legal requirement for infected people to isolate in England was scrapped. It has also been switched from law to guidance in Northern Ireland.
However, people are still required to isolate for at least one week in Scotland and six days in Wales.
Outside of the UK, isolation duration periods vary from four days in Norway to 10 days in Germany.
Dr Irwin-Knoester said a seven-day isolation period ‘should be safe’ in almost all cases, but five days ‘strikes an acceptable balance’ between the infectiousness of the virus and the desire to get back to normal.
Dr Irwin-Knoester is expected to tell the European Congress of Clinical Microbiology and Infectious Diseases: ‘The decisions being made by different countries around the world to shorten the period of isolation for Omicron infections are partly based on evidence from modeling.’
And she noted the move also takes account ‘of the fact that Omicron is causing less severe disease, and fewer hospitalizations and deaths’.
She said: ‘It is a way of returning to something like normal life and accept transmission of this less dangerous Omicron variant.
‘From the evidence so far, I am not convinced that a person is likely to be infectious for a shorter period of time with Omicron as they would have been with previous variants.’
Dr Irwin-Knoester said a maximum of seven days isolation ‘should be safe in almost all cases of infection’.
But a five-day isolation period ‘strikes an acceptable balance between the infectiousness of the virus and what most communities are willing to accept going forward, especially after around two years of restrictions in many cases’, she added.
However, Dr Irwin-Knoester noted that people still suffering from respiratory symptoms, such as coughing and sneezing, after seven days should continue to isolate for 10 to 14 days.
And those severely unwell with the virus often ‘shed for longer’, while immunocompromised people can transmit the virus for months.
Dr Irwin-Knoester also warned that a new variant ‘could throw everything up in the air’, especially if it causes more serious illness or escapes the protection offered by Covid vaccines.
‘If it is a new variant that makes us seriously ill, I would recommend returning to longer periods of isolation – with seven days as a minimum,’ she added.
In England, the legal requirement to self-isolate after testing positive came to an end on February 24, although people are still advised to do so.
The requirement to wear face masks also came to an end on that date, while free tests are being scrapped from April 1.